Full details of the Record Office's large collection of Parish Registers at Devon Heritage Services in Exeter and Barnstaple are given by the South West Heritage Trust in their Devon Parish Register List. This lists the years covered by the various registers, for baptisms, marriages and burials, and noting any lengthy gaps in coverage. It also indicates which of the branches of the Devon Record Office hold the original registers. The non-parochial register holdings include ones from Baptist, Congregational, Evangelical, Methodist, Quaker, Roman Catholic, and Unitarian churches and chapels. The civil registers are mainly from cemeteries and workhouses.
The Plymouth and West Devon Record Office provides this information about their holdings of Church Records - original parish registers for baptisms, marriages and burials for churches in Plymouth, Devonport and East Stonehouse as well as those in the south west Devon area, and similar registers for non-conformist chapels and churches and other places of worship in Plymouth, West Devon and East Cornwall.
Here are details, provided by the South West Heritage Trust, of the Coverage of Devon parish registers online on Find My Past, as of November 2014. These cover both the PRs held by Devon Heritage Services, and the Plymouth and West Devon Record Office. Included are lists of Missing Parish Registers, Parishes not yet included on Find My Past, and Parishes which will not be included on Find My Past.
See the South West Heritage's page Services We Provide for details of their professional genealogical research service. The Plymouth and West Devon Record Office provide an enquiry service and, though they do not provide a research service, do make available a list of independent Archive Researchers - see their page About the Archives.